[tip:timers/core] clocksource/drivers/ti-32k: Prevent ftrace recursion

From: tip-bot for Jisheng Zhang
Date: Thu Sep 22 2016 - 10:55:05 EST

Commit-ID: 3aa601492babdf3acdec89e5aa9c44e1a357a4d8
Gitweb: http://git.kernel.org/tip/3aa601492babdf3acdec89e5aa9c44e1a357a4d8
Author: Jisheng Zhang <jszhang@xxxxxxxxxxx>
AuthorDate: Thu, 22 Sep 2016 15:56:21 +0800
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 22 Sep 2016 16:49:19 +0200

clocksource/drivers/ti-32k: Prevent ftrace recursion

Currently ti-32k can be used as a scheduler clock. We properly marked
omap_32k_read_sched_clock() as notrace but we then call another
function ti_32k_read_cycles() that _wasn't_ notrace.

Having a traceable function in the sched_clock() path leads to a
recursion within ftrace and a kernel crash.

Fix this by adding notrace attribute to the ti_32k_read_cycles()

Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
Cc: daniel.lezcano@xxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20160922075621.3725-1-jszhang@xxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

drivers/clocksource/timer-ti-32k.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clocksource/timer-ti-32k.c b/drivers/clocksource/timer-ti-32k.c
index 92b7e39..cf5b14e 100644
--- a/drivers/clocksource/timer-ti-32k.c
+++ b/drivers/clocksource/timer-ti-32k.c
@@ -65,7 +65,7 @@ static inline struct ti_32k *to_ti_32k(struct clocksource *cs)
return container_of(cs, struct ti_32k, cs);

-static cycle_t ti_32k_read_cycles(struct clocksource *cs)
+static cycle_t notrace ti_32k_read_cycles(struct clocksource *cs)
struct ti_32k *ti = to_ti_32k(cs);